Decimal-point printing mechanism for electronic calculator

ABSTRACT

A decimal-point printing mechanism for an electronic calculator having a plurality of rockably mounted print hammers actuated selectively to engage a print drum or roll having type thereon for printing numerals. The type includes decimal points printed in their proper place in a multi-numeral number. Some of the print hammers have slidably disposed on a side thereof decimal point print levers that are actuated selectively from a rest position in which they are ineffective during the printing action of the respective print hammers. Selector mechanism is provided for selectively actuating individual decimal-point print levers to a raised position on the associated hammers for disposing the print heads thereof in position for printing a respective decimal point simultaneously with the printing effected by the associated print hammers.

[4 1 Dec. 25, 1973 1 DECIMAL-POINT PRINTING MECHANISM FOR ELECTRONIC CALCULATOR [75] Inventors: Masaaki Oishi, Tokyo; Yoshinaga Takahashi, Yachiyo; Keiichi Yoshizawa, Matsudo, all of Japan [73] Assignee: Kabushiki Kaisha Hattori Tokeiten,

Tokyo, Japan 22 Filed: July 8, 1971 21 Appl. No.: 160,685

[52] U.S. Cl. 101/93 C, 101/93 R [51] Int. Cl B41j l/16 [58] Field of Search 101/93 R, 93 C, 287, 101/95, 99; 235/60 [56] References Cited UNITED STATES PATENTS 3,138,325 6/1964 Stephen 101/93 R X 3,292,531 12/1966 Mutz 101/93 C 3,426,676 2/1969 Zielke 1 101/93 R 3,107,607 10/1963 Chall et al 101/93 R 3,051,082 8/1962 Hagemann 101/93 R 3,016,007 l/l962 Gelling 1 101/93 R 3,455,504 7/1969 Beikufner 101/93 R X Gang 101/93 R Heinze et a1. 101/93 R Primary Examiner-Robert E. Pulfrey Assistant ExaminerE. M, Coven Attorney-Robert E. Burns et a1.

[57] ABSTRACT A decimal-point printing mechanism for an electronic calculator having a plurality of rockably mounted print hammers actuated selectively to engage a print drum or roll having type thereon for printing numerals. The type includes decimal points printed in their proper place in a multi-numeral number. Some of the print hammers have slidably disposed on a side thereof decimal point print levers that are actuated selectively from a rest position in which they are ineffective during the printing action of the respective print hammers. Selector mechanism is provided for selectively actuating individual decimal-point print levers to a raised position on the associated hammers for disposing the print heads thereof in position for printing a respective decimal point simultaneously with the printing effected by the associated print hammers.

3 Claims, 11 Drawing Figures PATENTEH DEC 2 5 I975 SHfII 2 [1f 7 DECIMAL-POINT PRINTING MECHANISM FOR ELECTRONIC CALCULATOR BACKGROUND OF THE INVENTION DESCRIPTION OF PRIOR ART Heretofore, in order to print a decimal point in an electronic calculator, the decimal point type has been formed, along with the types of numerals, on the surface of a print drum. The electric input corresponding to a decimal-point print signal, drives or actuates a driving unit consisting of an electromagnet, a hammer, etc. for printing the decimal point, as in the case of the printing of the numerals. The known printing mechanisms therefore have been disadvantageous in, e.g., that an electric circuit, the electromagnet, the hammer, etc. is required for printing a decimal-point. The known circuit arrangement are complicated, the equipment is large, and a large space for it is necessary.

SUMMARY OF THE INVENTION The present invention has as its object eliminating the above-mentioned disadvantages of the prior art, and in providing a decimal-point printing mechanism for an electronic calculator, which is simple in construction.

According to the present invention, there is provided a decimal-point printing device for an electronic calculator, comprising a print drum, at least one rockably supported print hammer having a print head at a position opposite or opposed to the print drum. The print hammer is rockably supported and is selectively actuated to effect printing. A decimal-point print lever is slidably supported on a side of the print hammer and has 'a print'head. A rockable. decimal-point changeover lever engageable selectively with the lower end of the decimal-point print lever slides the decimal-point print lever relative to the print hammer to a position in which its print head engages the decimal point type on the print drum when the print hammer is rocked to a position where its print head engages the print drum.

BRIEF DESCRIPTION OF THE DRAWINGS Other objects and characteristic features of the present invention will become evident and will be more readily understood by the following description and claims taken in conjunction with the accompanying drawings, in which:

FIG. 1 is an elevation view of a mechanism according to the present invention;

FIG. 2 is an elevation view of the mechanism of FIG. 1 in another operative position;

FIG. 3 is an elevation view of a decimal-point change-over mechanism according to the present invention;

FIG. 4 is an elevation view of the mechanism of FIG. 3 illustrating another operative position thereof;

FIG. 5 is an elevation view of the mechanism of FIG. 3 in still another operative state or position;

FIG. 6 is an elevation view of a cam;

FIG. 7 is an elevation view of another cam;

FIG. 8 is an elevation view of still another cam;

FIG. 9 is a side elevation view of the mechanism of FIG. 3.

FIG. 10 is a diagrammatic fragmentary developed view of a print roll in an apparatus embodying the invention, and

FIG. ,11 is a diagrammatic plan view of the print roll in FIGS. 1 & 10.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1 a print drum 1 of an electronic calculator embodying the invention is illustrated. The print drum has type formed at suitable intervals on its outer periphery. The type corresponds to numerals and to decimal points as shown in FIGS. 10 and 11. A hammer head 2 of a hammer 3 is disposed at a position spaced from and opposed to the print drum 1. The hammer is supported on a shaft 4 and is rockable to engage the hammer head with the print drumtype. The hammer 3 is urged away from the print drum by means of a spring 5, and is stopped in travel to engage the print drum by means of a stop 6. At a terminal or lower part of the hammer 3, a hammer claw 8 is rockably supported on a shaft 7. The hammer claw 8 and the hammer 3 are respectively provided with apertures 9 and 10, in which opposite ends of a coupling spring 11 are engaged. A pair of stops l2, 13 for the hammer claw 8 are provided on the print hammer. The coupling spring 11 biases the hammer claw into engagement with the stop 13 on the hammer 3. The hammer 3 is rocked and driven through the hammer claw 8 which is activated by means of a print driving mechanism, not shown. The hammer head 2 strikes the print drum 1 when rocked to engage the print drum thereby to effect printing.

A decimal-point print lever is slidably mounted on a front side of the hammer 3. The hammer support shaft 4 extends through a guide slot 15 formed in the decimal-point print lever 14. A guide slot 16 is provided and a guide pin 17 secured to the hammer 3 penetrates through the guide slot 16, and a return spring 18 is connected between the decimal-point print lever 14 and the hammer 3. The decimal-point print lever 14 is biased or drawn downwardly by the return spring 18, and a print head 19, thereof is normally positioned below the hammer head 2. A decimal point is formed as type on the print drum 1 opposed to the decimal-point print lever 14. The decimal-point print lever 14 is mounted on the print hammer in place adjacent to the position at which the decimal point is to be printed.

A change-over lever 21 is supported on a shaft 20 in a rockable manner and a front end 22 thereof is positioned in proximity to a lower end of the decimal-point print lever 14. When the change-over lever 21 is located in the position shown in FIG. 1, its front end 22 does not push upwardly the decimal-point print lever 14. Therefore, the print head 19 is not aligned with the hammer print head 2. For this reason, even if the print hammer 3 is driven to effect printing no decimal point is printed in the condition or state of the device illustrated in FIG. 1.

When the change-over 21 is rocked, by the print control or driving mechanism, to move its front end 22 upwardly in the direction of the arrow shown in FIG. 1, the decimal-point print lever 14 is pushed upwardly and it slides upwards on the hammer 3. Its print head 19 is thus aligned with the hammer print head 2 in the position shown in FIG. 2. As a result, when the print mal point print head 19 strikes the print drum for the decimal point and prints it.

3 Assuming now that the positions at which the decimal points are printable at, for example, every third place, or more specifically that the decimal points are printable at a position a before the first place, at a position b before the fourth-place and at a position before the seventh place, in a numeral 1 2 3 c 4 5 6 b 7 8 9 a, then the decimal-point print levers as described above are provided on the respective print hammers in the first, fourth and seventh places and in a slidable manner as before described. In addition the change-over levers of the construction described above are respectively disposed to actuate their associated decimal-point print levers. Although the respective change-over levers may be individually rocked, change-over cams may be provided instead to connect therewith a device which selects and changes over the decimal point to be printed. This type of decimal-point change-over device is constructed as stated below.

FIG. 3 illustrates an example in which a decimal point is put at the position a. More specifically, referring now to FIGS. 3 to 9 the change-over shaft in this embodiment has three change-over levers 21a, 21b and 21c carried thereon and rockable thereby. Each change-over lever is kept in contact at one end with a corresponding one of decimal-point print levers 14a, 14b and 140. Each decimal-point print lever has a side projection at the other end each formed by a pin 23a, 23b or 230, respectively. The change-over levers are individually biased in a clockwise direction by means of respective springs 24a, 24b and 24c. A plurality of change-over cams 25a, 25b and 25c is provided and these cams are respectively engageable with the pins 23a, 23b and 230 are secured at suitable intervals by a spacer 26and a linking rod 27. A change-over handle 28 is secured at an end of the spacer 26. The spacer 26 is rotatably mounted on a shaft 29. The pins 23a, 23b and 23c are kept in resilient contact with the changeover cams 25a, 25b and 250 by means of the springs 24a, 24b and 24c, respectively. A permanent magnet 30 is secured to the change-over handle 28. At changeover positions opposed to the magnet 30, there are secured reed switches 31, 32 and 33.

' In operation, when a decimal point is printed at the position a, the change-over cam 25a as shown in FIG. 6 governs the printing of the corresponding decimal point. In this embodiment, construction is such that, when the decimal point is put at the position a, the decimal point is not printed. More specifically, as illustrated in FIG. 3, the respective pins 23a, 23b and 230 of the change-over levers are kept in contact with bottoms of the respective change-over cams 25a, 25b and 250. Accordingly, the change-over levers 21a, 21b and 210 are not rocked, so that the printing of the decimal point is not executed. However, since the change-over handle 28 is located as shown in FIG. 3, the magnet 30 is opposed to the reed switch 31, and through the function of this reed switch, an operation is carried out with the decimal point at the position a.

When the decimal point is put at the position b, the change-over cam 25b shown in FIG. 7 governs the printing of the corresponding decimal point. The change-over handle 28 is displaced to the position shown in FIG. 4, the magnet 30 is opposed to the reed switch 32, and an operation command. corresponding to the position b decimal point is issued. At that time, a crest 34 formed on the cam face of the change-over cam 25b pushes down the pin 23b in a counterclockwise direction, with the result that the front end 22 of the change-over lever 21b pushes up the decimal-point print lever 14b. The printing of the decimal point is accordingly performed. Since the respective pins 23a and 230 of the change-over levers.2la and 21c are held in contact with the bottoms of the respective cams 25a and 25c, the printing of the decimal points at the position a and the position b is not effected.

Further, when the decimal point is put at the position 0, the change-over cam 250 as illustrated in FIG. 8 governs the printing of the corresponding decimal point. When the change-over handle is displaced to the position shown in FIG. 5, the magnet 30 is disposed opposed to the reed switch 33, and an operation command of the position c decimal point is issued. At that time, the pin 230 is pushed down in a counterclockwise direction against the spring 240. by means of a crest 35 of the change-over cam 250, the change-over lever 210 is rocked, and the decimal-point print lever 140 is pushed up, thereby effecting the printing of the decimal point. The respective pins 23a and 23b of the changeover levers 21a and 21b are kept in contact with the bottoms of the respective cams 25a and 25!), so that the decimal points at the position a and the position b are not printed.

In this manner, according to the selection and change-over device, when the single change-over handle is displaced to a desired, decimal-point printing position, only the change-over cam corresponding thereto actuates its respective change-over lever and only the desired decimal point is thus printed.

The selection and change-over device is not restricted to the embodiments described above. The decimal points may be optionally selected in number and in position and the number and configuration of the change-over levers and change-over camsmay be constructed accordingly.

Those skilled in the art will understand that one print hammer has been shown to simplify the drawings, however, the electronic calculator embodying the invention has a plurality of print hammers for printing numerals at different place values of numbers and certain ones of these have a decimal-point print lever slidably supported thereon. The decimal points are, of course, at the place values, of multi-numeral numbers, in which decimal points occur. Thus only one set of a print hammer and its associated decimal-point print levers have been shown but a multiplity of these are used and they form a subset of a larger set of print hammers including the above-mentioned subset and other print hammers without decimal-point print levers.

What we claim and desire to secure by Letters Patent are:

l. A decimal point printing mechanism for a calculator comprising, a print drum having type formed on the periphery thereof including type corresponding to a decimal point, at least one rockably supported print hammer having a print head spaced from said print drum and movable selectively to an operative position engaging said print head with said print drum to effect printing with said type other than said decimal point, means rockably supporting said print hammer, means operable (selectively) to selectively actuate said print hammer to rock said print hammer print head into en gagement with said print drum type other than said type corresponding to said decimal point, a decimal point print lever slidably supported on said print hammer for transportation thereby and for simultaneous movement therewith from a rest position of the print hammer to an operative position thereof and back to the rest position and having a print head rocked in conjunction with said print hammer, means mounting said decimal point print lever slidably on said print hammer with the print head thereof in a position relative to said print hammer in which it is clear of said print drum when the print hammer print head engages said print drum type in said operative position, means to selectively slide said decimal point print lever relatively to said print hammer to move the print head thereof toa position for engaging the type on said print drum corresponding to said decimal point when said print head of said print hammer is in said operative position and engages type on said print drum, and means to restore said decimal point print lever to said position relative to said print hammer in which the print head thereof is clear of said print drum when said print hammer is actuated into engagement with said type on said print drum.

2. A decimal point printing mechanism for a calculator according to claim 1, in which said means to selectively slide said decimal point print lever relatively to said print hammer comprises a change-over lever operable selectively to engage said decimal point print lever.

3. A decimal point printing mechanism for a calculator according to claim 2, in which said print hammer and said decimal point (respective) print heads are disposed in registry side-by-side when said decimal point print lever is in readiness for printing, thereby to effect printing of said decimal point simultaneously with printing other than a decimal point. 

1. A decimal point printing mechanism for a calculator comprising, a print drum having type formed on the periphery thereof including type corresponding to a decimal point, at least one rockably supported print hammer having a print head spaced from said print drum and movable selectively to an operative position engaging said print head with said print drum to effect printing with said type other than said decimal point, means rockably supporting said print hammer, means operable (selectively) to selectively actuate said print hammer to rock said print hammer print head into engagement with said print drum type other than said type corresponding to said decimal point, a decimal point print lever slidably supported on said print hammer for transportation thereby and for simultaneous movement therewith from a rest position of the print hammer to an operative position thereof and back to the rest position and having a print head rocked in conjunction with said print hammer, means mounting said decimal point print lever slidably on said print hammer with the print head thereof in a position rElative to said print hammer in which it is clear of said print drum when the print hammer print head engages said print drum type in said operative position, means to selectively slide said decimal point print lever relatively to said print hammer to move the print head thereof to a position for engaging the type on said print drum corresponding to said decimal point when said print head of said print hammer is in said operative position and engages type on said print drum, and means to restore said decimal point print lever to said position relative to said print hammer in which the print head thereof is clear of said print drum when said print hammer is actuated into engagement with said type on said print drum.
 2. A decimal point printing mechanism for a calculator according to claim 1, in which said means to selectively slide said decimal point print lever relatively to said print hammer comprises a change-over lever operable selectively to engage said decimal point print lever.
 3. A decimal point printing mechanism for a calculator according to claim 2, in which said print hammer and said decimal point (respective) print heads are disposed in registry side-by-side when said decimal point print lever is in readiness for printing, thereby to effect printing of said decimal point simultaneously with printing other than a decimal point. 